Genome-wide identification and expression analysis of the ADH gene family under diverse stresses in tobacco (Nicotiana tabacum L.)

BACKGROUND

Alcohol dehydrogenases (ADHs) are the crucial enzymes that can convert ethanol into acetaldehyde. In tobacco, members of ADH gene family are involved in various stresses tolerance reactions, lipid metabolism and pathways related to plant development. It will be of great application significance to analyze the ADH gene family and expression profile under various stresses in tobacco.

RESULTS

A total of 53 ADH genes were identified in tobacco (Nicotiana tabacum L.) genome and were grouped into 6 subfamilies based on phylogenetic analysis. Gene structure (exon/intron) and protein motifs were highly conserved among the NtADH genes, especially the members within the same subfamily. A total of 5 gene pairs of tandem duplication, and 3 gene pairs of segmental duplication were identified based on the analysis of gene duplication events. Cis-regulatory elements of the NtADH promoters participated in cell development, plant hormones, environmental stress, and light responsiveness. The analysis of expression profile showed that NtADH genes were widely expressed in topping stress and leaf senescence. However, the expression patterns of different members appeared to be diverse. The qRT-PCR analysis of 13 NtADH genes displayed their differential expression pattern in response to the bacterial pathogen Ralstonia solanacearum L.

INFECTION

Metabolomics analysis revealed that NtADH genes were primarily associated with carbohydrate metabolism, and moreover, four NtADH genes (NtADH20/24/48/51) were notably involved in the pathway of alpha-linolenic acid metabolism which related to the up-regulation of 9-hydroxy-12-oxo-10(E), 15(Z)-octadecadienoic acid and 9-hydroxy-12-oxo-15(Z)-octadecenoic acid.

CONCLUSION

The genome-wide identification, evolutionary analysis, expression profiling, and exploration of related metabolites and metabolic pathways associated with NtADH genes have yielded valuable insights into the roles of these genes in response to various stresses. Our results could provide a basis for functional analysis of NtADH gene family under stressful conditions.

Genome-wide identification and expression analysis of the R2R3-MYB gene family in tobacco (Nicotiana tabacum L.)

BACKGROUND

The R2R3-MYB transcription factor is one of the largest gene families in plants and involved in the regulation of plant development, hormone signal transduction, biotic and abiotic stresses. Tobacco is one of the most important model plants. Therefore, it will be of great significance to investigate the R2R3-MYB gene family and their expression patterns under abiotic stress and senescence in tobacco.

RESULTS

A total of 174 R2R3-MYB genes were identified from tobacco (Nicotiana tabacum L.) genome and were divided into 24 subgroups based on phylogenetic analysis. Gene structure (exon/intron) and protein motifs were especially conserved among the NtR2R3-MYB genes, especially members within the same subgroup. The NtR2R3-MYB genes were distributed on 24 tobacco chromosomes. Analysis of gene duplication events obtained 3 pairs of tandem duplication genes and 62 pairs of segmental duplication genes, suggesting that segmental duplications is the major pattern for R2R3-MYB gene family expansion in tobacco. Cis-regulatory elements of the NtR2R3-MYB promoters were involved in cellular development, phytohormones, environmental stress and photoresponsive. Expression profile analysis showed that NtR2R3-MYB genes were widely expressed in different maturity tobacco leaves, and however, the expression patterns of different members appeared to be diverse. The qRT-PCR analysis of 15 NtR2R3-MYBs confirmed their differential expression under different abiotic stresses (cold, salt and drought), and notably, NtMYB46 was significantly up-regulated under three treatments.

CONCLUSIONS

In summary, a genome-wide identification, evolutionary and expression analysis of R2R3-MYB gene family in tobacco were conducted. Our results provided a solid foundation for further biological functional study of NtR2R3-MYB genes in tobacco.